orjson VS polars

Compare orjson vs polars and see what are their differences.

orjson

Fast, correct Python JSON library supporting dataclasses, datetimes, and numpy (by ijl)

polars

Dataframes powered by a multithreaded, vectorized query engine, written in Rust (by ritchie46)
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orjson polars
22 151
7,137 34,403
2.7% 1.6%
8.0 10.0
5 days ago 3 days ago
Python Rust
Apache License 2.0 GNU General Public License v3.0 or later
The number of mentions indicates the total number of mentions that we've tracked plus the number of user suggested alternatives.
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.

orjson

Posts with mentions or reviews of orjson. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2024-09-28.

polars

Posts with mentions or reviews of polars. We have used some of these posts to build our list of alternatives and similar projects. The last one was on 2025-05-29.
  • ClickHouse raises $350M Series C
    7 projects | news.ycombinator.com | 29 May 2025
    Thanks for creating this issue, it is worth investigating!

    I see you also created similar issues in Polars: https://github.com/pola-rs/polars/issues/17932 and DuckDB: https://github.com/duckdb/duckdb/issues/17066

    ClickHouse has a built-in memory tracker, so even if there is not enough memory, it will stop the query and send an exception to the client, instead of crashing. It also allows fair sharing of memory between different workloads.

    You need to provide more info on the issue for reproduction, e.g., how to fill the tables. 16 GB of memory should be enough even for a CROSS JOIN between a 10 billion-row and a 100-row table, because it is processed in a streaming fashion without accumulating a large amount of data in memory. The same should be true for a merge join.

    However, there are places when a large buffer might be needed. For example, if you insert data into a table backed by S3 storage, it requires a buffer that can be in the order of 500 MB.

    There is a possibility that your machine has 16 GB of memory, but most of it is consumed by Chrome, Slack, or Safari, and not much is left for ClickHouse server.

  • Debugging Data Pipelines: From Memory to File with WebDAV
    6 projects | dev.to | 3 May 2025
    (* There might be no file or even file-like thing. You may be working with data frames (Pandas or Polars), event streams, and whatnot.)
  • Using Polars in Rust for high-performance data analysis
    9 projects | dev.to | 30 Oct 2024
    If you want to get into Polars, the library is very well documented, and I’d recommend you check out their getting started tutorial, their API docs, and when you’re all set up, you can also check out their Cookbooks to learn about many of the standard operations within Polars.
  • Why Polars rewrote its Arrow string data type
    4 projects | news.ycombinator.com | 6 Aug 2024
    This is false. The polars api has used smart string for a long time.

    https://github.com/pola-rs/polars/blob/32a2325b55f9bce81d019...

  • Polars releases v1.0.0 – a Pandas alternative
    1 project | news.ycombinator.com | 1 Jul 2024
  • Polars Releases v1.0.0
    1 project | news.ycombinator.com | 11 Jun 2024
  • Big Data Is Dead
    3 projects | news.ycombinator.com | 27 May 2024
  • Why Python's Integer Division Floors (2010)
    1 project | news.ycombinator.com | 28 Feb 2024
    This is because 0.1 is in actuality the floating point value value 0.1000000000000000055511151231257827021181583404541015625, and thus 1 divided by it is ever so slightly smaller than 10. Nevertheless, fpround(1 / fpround(1 / 10)) = 10 exactly.

    I found out about this recently because in Polars I defined a // b for floats to be (a / b).floor(), which does return 10 for this computation. Since Python's correctly-rounded division is rather expensive, I chose to stick to this (more context: https://github.com/pola-rs/polars/issues/14596#issuecomment-...).

  • Polars
    11 projects | news.ycombinator.com | 8 Jan 2024
    https://github.com/pola-rs/polars/releases/tag/py-0.19.0
  • Stuff I Learned during Hanukkah of Data 2023
    5 projects | dev.to | 18 Dec 2023
    That turned out to be related to pola-rs/polars#11912, and this linked comment provided a deceptively simple solution - use PARSE_DECLTYPES when creating the connection:

What are some alternatives?

When comparing orjson and polars you can also consider the following projects:

msgspec - A fast serialization and validation library, with builtin support for JSON, MessagePack, YAML, and TOML

Daft - Distributed query engine providing simple and reliable data processing for any modality and scale

ujson

DataFrames.jl - In-memory tabular data in Julia

ormsgpack - Msgpack serialization/deserialization library for Python, written in Rust using PyO3. Reboot of orjson. msgpack.org[Python]

vaex - Out-of-Core hybrid Apache Arrow/NumPy DataFrame for Python, ML, visualization and exploration of big tabular data at a billion rows per second 🚀

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InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.
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Stream - Scalable APIs for Chat, Feeds, Moderation, & Video.
Stream helps developers build engaging apps that scale to millions with performant and flexible Chat, Feeds, Moderation, and Video APIs and SDKs powered by a global edge network and enterprise-grade infrastructure.
getstream.io
featured

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